Re: [PATCH 12/18] nvme-fabrics: parse options 'keyring' and 'tls_key'

Hannes Reinecke
2023-03-30T17:34:36Z

On 3/30/23 17:33, Sagi Grimberg wrote:
>> Parse the fabrics options 'keyring' and 'tls_key' and store the
>> referenced keys in the options structure.
>
> Can you explain the reasoning to why a user need to pass a keyring
> given that we already set up one?
>
Choice.
With a single keyring we can only have a single identity.
But there might be configurations where we want to have different PSKs
for the same identity (eg for key rotation).
With this option we can prepare a new keyring, and use that instead of
the old one.

(And it really doesn't add much complexity...)

>>
>> Signed-off-by: Hannes Reinecke <hare@suse.de>
>> ---
>>   drivers/nvme/host/fabrics.c | 79 ++++++++++++++++++++++++++++++++++++-
>>   drivers/nvme/host/fabrics.h |  6 +++
>>   drivers/nvme/host/tcp.c     | 20 +++++++---
>>   3 files changed, 98 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/nvme/host/fabrics.c b/drivers/nvme/host/fabrics.c
>> index 3e4f0e45b58f..5f5e487d498c 100644
>> --- a/drivers/nvme/host/fabrics.c
>> +++ b/drivers/nvme/host/fabrics.c
>> @@ -605,6 +605,8 @@ static const match_table_t opt_tokens = {
>>       { NVMF_OPT_NR_WRITE_QUEUES,    "nr_write_queues=%d"    },
>>       { NVMF_OPT_NR_POLL_QUEUES,    "nr_poll_queues=%d"    },
>>       { NVMF_OPT_TOS,            "tos=%d"        },
>> +    { NVMF_OPT_KEYRING,        "keyring=%d"        },
>> +    { NVMF_OPT_TLS_KEY,        "tls_key=%d"        },
>>       { NVMF_OPT_FAIL_FAST_TMO,    "fast_io_fail_tmo=%d"    },
>>       { NVMF_OPT_DISCOVERY,        "discovery"        },
>>       { NVMF_OPT_DHCHAP_SECRET,    "dhchap_secret=%s"    },
>> @@ -620,8 +622,9 @@ static int nvmf_parse_options(struct
>> nvmf_ctrl_options *opts,
>>       char *options, *o, *p;
>>       int token, ret = 0;
>>       size_t nqnlen  = 0;
>> -    int ctrl_loss_tmo = NVMF_DEF_CTRL_LOSS_TMO;
>> +    int ctrl_loss_tmo = NVMF_DEF_CTRL_LOSS_TMO, key_id;
>>       uuid_t hostid;
>> +    struct key *key = NULL;
>>       /* Set defaults */
>>       opts->queue_size = NVMF_DEF_QUEUE_SIZE;
>> @@ -889,6 +892,74 @@ static int nvmf_parse_options(struct
>> nvmf_ctrl_options *opts,
>>               }
>>               opts->tos = token;
>>               break;
>> +        case NVMF_OPT_KEYRING:
>> +#ifdef CONFIG_NVME_TLS
>
> Same comment as before:
>             if (!IS_ENABLED(CONFIG_NVME_TLS)) {
>                 pr_err("TLS is not supported\n");
>                 ret = -EINVAL;
>                 goto out;
>             }
>
OK.

>> +            if (match_int(args, &key_id)) {
>> +                ret = -EINVAL;
>> +                goto out;
>> +            }
>> +            if (key_id < 0) {
>> +                pr_err("Invalid keyring id %d\n", key_id);
>> +                ret = -EINVAL;
>> +                goto out;
>> +            }
>> +            if (!key_id) {
>> +                pr_debug("Using default keyring\n");
>> +                if (opts->keyring) {
>> +                    key_put(opts->keyring);
>> +                    opts->keyring = NULL;
>> +                }
>> +                break;
>> +            }
>> +            key = key_lookup(key_id);
>> +            if (!key) {
>> +                pr_err("Keyring id %08x not found\n", key_id);
>> +                ret = -ENOKEY;
>> +                goto out;
>> +            }
>> +            if (opts->keyring)
>> +                key_put(opts->keyring);
>> +            opts->keyring = key;
>> +            break;
>> +#else
>> +            pr_err("TLS is not supported\n");
>> +            ret = -EINVAL;
>> +            goto out;
>> +#endif
>> +        case NVMF_OPT_TLS_KEY:
>> +#ifdef CONFIG_NVME_TLS
>> +            if (match_int(args, &key_id)) {
>> +                ret = -EINVAL;
>> +                goto out;
>> +            }
>> +            if (key_id < 0) {
>> +                pr_err("Invalid key id %d\n", key_id);
>> +                ret = -EINVAL;
>> +                goto out;
>> +            }
>> +            if (!key_id) {
>> +                pr_debug("Using 'best' PSK\n");
>> +                if (opts->tls_key) {
>> +                    key_put(opts->tls_key);
>> +                    opts->tls_key = NULL;
>> +                }
>> +                break;
>> +            }
>> +            key = key_lookup(key_id);
>> +            if (!key) {
>> +                pr_err("Key id %08x not found\n", key_id);
>> +                ret = -ENOKEY;
>> +                goto out;
>> +            }
>> +            if (opts->tls_key)
>> +                key_put(opts->tls_key);
>> +            opts->tls_key = key;
>> +#else
>> +            pr_err("TLS is not supported\n");
>> +            ret = -EINVAL;
>> +            goto out;
>> +#endif
>> +            break;
>>           case NVMF_OPT_DISCOVERY:
>>               opts->discovery_nqn = true;
>>               break;
>> @@ -1054,6 +1125,12 @@ static int nvmf_check_allowed_opts(struct
>> nvmf_ctrl_options *opts,
>>   void nvmf_free_options(struct nvmf_ctrl_options *opts)
>>   {
>>       nvmf_host_put(opts->host);
>> +#ifdef CONFIG_NVME_TLS
>> +    if (opts->keyring)
>> +        key_put(opts->keyring);
>> +    if (opts->tls_key)
>> +        key_put(opts->tls_key);
>
> I think key_put is null safe.

Possibly. I'll check.

Cheers,

Hannes
--
Dr. Hannes Reinecke Kernel Storage Architect
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